[majormajor]

It's much easier for the inclination of an [a single] individual to be due to the perception of [just a single] individual, than if the impetus is a team-level inclination.

I've worked on projects where people had gripes about the codebase and/or language, but they often couldn't agree on which language to move to. So a single person taking over based on their own preference is either a bug or a feature: as a bug, it's ignoring everyone else's preferences and disagreements, and possibly moving to something the team is even less happy with. As a feature, it's making a decision instead of endlessly trying to find a perfect decision, and at least ending up somewhere better off than before.

In this case, it sounds like it could be the positive sort of change if only because they were starting from a basically-dead language. It sounds like without that single person's initial effort, they may have not started any effort to migrate to anything.

But this gives me major pause: "My colleagues will continue to develop in Extended Pascal as usual, and once my transpiler is able to translate all or almost all of it, we will make the switch to D overnight." I'd love to fast-forward to see what happens the days after that... and how long that takes to get to, for that matter!